Augmenting and reflecting conical combustion chamber



Patented Mar. 10, 1953 UNITED STATES PATENT OFFICE AUGMENTING: AND REFLECTING CONICAL COMBUSTION CHAlWBER Application March 24, 1948, Serial No. 16,866

4 Claims. 1

This invention relates to combustion chambers as used in propulsion apparatus and relates more particularly to combustion chambers of the general type shown in the prior Goddard Patent No. 2,396,566, issued March 12, 1946.

In this type of apparatus, an elongated explosive charge is detonated in spaced relation to a substantially conical combustion chamber which is entirely open at the rear end thereof. The combustion gases from the detonated charge spread out radially and are reflected rearwardly by the inner conical surface of the chamber.

It is the general object of the present invention to provide a conical combustion chamber so constructed that the volume of the combustion gases will. be augmented by atmospheric air as these gases are reflected rearward. The mass of the rearwardly discharged combustion gases is thus substantially increased and improved propulsive results are attained.

The invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

Preferred forms of the invention are shown in the drawing, in which Fig. 1 is a sectional side elevation of a conical combustion chamber embodying this invention;

Fig. 2 is a partial plan view, looking in the direction of the arrow 2 in Fig. 1; and

Figs. 3, 4 and 5 are views similar to Fig. l but showing modified constructions.

Referring to Figs. 1 and 2, a conical combustion chamber C is shown as comprising an axial member I0 and a series of axially aligned frustoconical members ll, I2 and I3. The members H, l2 and I3 are of tubular cross section, and the inner reflecting surfaces R thereof are preferably straight in their upper portions and at an angle of substantially 45, as indicated at I5, and each preferably have their lower edge portions I6 inwardly contracted.

The inner upper wall 20 of the member I! is outwardly curved, as shown in Fig. 1, and the outer wall 22 is inwardly contracted upwardly. The members I2 and I3 are of similar cross section.

An explosive charge is formed in the combustion chamber from intermingled combustion liquids, such as gasoline and liquid oxygen, which are injected through a feed pipe 24. The specific means for feeding the combustion mixture forms no part of this present invention.

As such an explosive charge is detonated, the combustion gases spread outward radially and are deflected axially by the reflecting surfaces R of the annular conical sections I0, II, I2 and I3. At the same time, a substantial mass of atmospheric air enters through the augmenter passages P and through annular slots 25, 26 and 2i provided between the spaced chamber sections I0,

5 I, I2 and I3.

These chamber sections or annular members I i, I2 and iii are retained in spaced and aligned relation by a plurality of connecting vanes 28. The inwardly curved lower edge surfaces I6 of the annular members II, I2 and I3 assist in diverting the combustion gases from the slots 25, 25 and 2'! and thus improve theaugmenting efiect by avoiding back pressure.

In the construction shown inFig. 3, a combustion chamber C is shown as comprising an axial feed member and a series of hollow annular frusto-conical members 3I, 32, 33 and 314, all connected by a plurality of vanes 35. The construction is similar to that shown in Fig, 1, except that the inner reflecting faces 31 of the annular members are entirely straight and preferably slanted at 45, but with the lower edge of each annular member positioned inwardly with respect to the next outward member and also additionally overlapping said member. Back pressure in the augmenter passages P is thus effectively avoided.

In Fig. 4 there is shown a feed member and a series of hollow annular frusto-conical members 4 I, 42 and 43 held in spaced relation by vanes M. The inner reflecting surfaces 45 are disposed at a more acute angle than the surfaces 31 in Fig. 3 but the diameters of the annular members are so selected that the lower edges of the mem-- bers 40, 4|, 42 and 43 would lie substantially in the surface of a 45 cone. With this construction, the combustion gases are reflected into a more compact stream than in the construction shown in Fig. 3.

In the construction shown in Fig. 5, a feed member and annular members 5i, 52 and 53 are held in spaced relation by vanes 55. The augmenting effect of this combustion chamber is increased by providing each annular member 5|, 52 and 53 with an inner upper conical surface 51 and with a cylindrical outer surface 53. A greater volume of air is thus directed to each of the annular ports 60, BI and 62.

This type of combustion chamber is desirable where the associated aircraft moves at relatively low speed or is in very thin atmosphere. It is found that the increased air-collecting capacity offsets the reduced augmenting effect.

Having thus described the invention and the c.) advantages thereof, it will be understood that the invention is not to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what is claimed is:

1. In an augmenting and reflecting combustion chamber comprising a substantially conical end wall having a plurality of annular wall members mounted in spaced relation and defining a series of annular augmenting passages terminating in a series of annular air-admitting slots, that improvement in which each annular wall member is substantially triangular in cross section, with upwardly converging inner and outer upper surfaces, and in which each annular wall member is formed with its inner upper surface convex and outwardly-and-upwardly curved and with its adjacent outer upper surface convex and inwardly-and-upwardly curved and said inner and outer upper surfaces defining augmenting passages which substantially increase in cross section upwardly and outwardly.

2. The combination in an augmenting and refleeting combustion chamber as set forth in claim 1, in which each wall member has a frusto-conical inner reflecting surface positioned between two adjacent air-admitting slots and in which each annular wall member has its inner reflecting surface formed at an angle of substantially 45 to the axis of the chamber, and in which the inner reflecting surfaces of successive wall members are relatively outwardly offset, so that the inner reflecting surface of each Wall member except the smallest will be positioned slightly outside of the surface of a cone defined by the inner reflecting surface of the next adjacent and smaller wall member.

3. The combination in an augmenting and reflecting combustion chamber as set forth in claim 1, in which each wall member has a frusto-conical inner reflecting surface positioned between two adjacent air-admitting slots and in which each annular wall member has its inner reflecting surface formed at an angle of substantially less than 45 to the axis of said chamber and in which corresponding points in successive wall members are substantially in a conical locus at 45 to the axis.

4. An augmenting and reflecting combustion chamber comprising a substantially conical end wall having a plurality of annular wall members mounted in spaced relation and defining a series of annular augmenting passages terminating in a series of annular air-admitting slots, each wall member having a frusto-conical inner reflecting surface positioned between two adjacent airadmitting slots and each annular wall member having its inner reflecting surface disposed sub-' stantially at 45 to the axis of said chamber in its upper portion and having its lower portion oflset and curved inwardly and away from the adjacent annular air-admitting slot.

ESTHER c. GODDARD, Executrizc of the last will and testament of Robert H. Goddard, deceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,322,999 Bester Nov. 25, 1919 1,410,708 Mosher Mar. 28, 1922 1,706,316 Norton et al Mar. 19, 1929 FOREIGN PATENTS Number Country Date 80,953 Austria July 10, 1920 336,947 Germany May 20, 1921 

